Sporadically over the last 100 years, there have been various attempts to fabricate shoe soles or insoles having internal springs. Early such devices are shown in U.S. Pat. Nos. 413,693, 507,490, 968,120, and 1,088,324. These early patents, like the more recent counter-part, U.S. Pat. No. 4,322,893, utilize helically wound coil springs as shock absorbing energy storage devices. A draw back with coil springs is their height relative to their diameter and their limited range. In order to minimize the collapsed height, conically wound coil springs have been utilized. The most significant problem of prior art coil springs is their limited energy storage capacity. Additionally, coil springs of conventional design are difficult to retain as their free ends cause load concentrations requiring rigid retainer plates as reinforcement structures, as shown in U.S. Pat. No. 2,668,374. U.S. Pat. No. 4,267,648 (Weisz) suggests several alternatives to coil springs, such as flat disk springs and belleville washer springs. In order to maintain a low profile, a large number of small springs are utilized.